In known water headers of this type, the oil radiator has two oil inlet and outlet tubular connectors which extend sealingly through a side wall of the water header, i.e. of the header cover. The oil cooler is retained and fixed within the header by means of these tubular connectors. The header cover has an open face. The two tubular connectors of the oil cooler are connected to an oil circuit, such as the engine and/or gearbox lubricating oil circuit of the motor vehicle. The oil which flows through the oil cooler is cooled by the liquid flowing in the heat exchanger of which the header forms a part, this heat exchanger being typically the engine cooling radiator of the vehicle.
In these known types of water header, the oil cooler or radiator is introduced through the open face of the header cover, before the latter is fitted onto the end of a bundle of tubes, or on a heat exchanger body which will be covered by the open face of the header cover.
The oil cooler conventionally comprises a cylindrical body consisting of two concentric tubes which are closed at their ends, and to which the two oil inlet and outlet tubular connectors are connected, these two connectors extending in directions parallel to each other and at right angles to the longitudinal direction of the body of the oil cooler. Each of these tubular connectors has a base portion which is brazed onto the cylindrical body of the oil cooler, together with a threaded portion which, in cooperation with a nut, enables the oil cooler to be fixed onto the side wall of the header cover, with a sealing gasket being interposed.
In order that the oil cooler can be fitted into the header cover, it is necessary that the latter should have an internal width which is at least equal to the overall size of the oil cooler in the same dimension, that is to say the overall width of the oil cooler including its tubular connectors. In other words, the internal width of the header cover has to be at least equal to the diameter of the cylindrical body of the oil cooler plus the length of its tubular connectors.
Therefore, the water header must have a relatively large internal width, which is substantially greater than the width (or corresponding dimension) of the tube bundles or bodies of current heat exchangers. The internal width of the header cover is therefore disproportionate with respect to the dimension of the tube bundle or body of the heat exchanger.
In practice, this makes it necessary to provide specially designed header covers, as well as special header plates and sealing gaskets, in place of conventional or standard header covers and header plates and sealing gaskets which also form part of the water header, when it is required to have an oil cooler inside the header. This problem leads to substantial increases in cost, and this effect is even more marked when special tooling or machinery is required for assembling the heat exchanger.
In order to overcome these drawbacks it has been proposed, as disclosed in French patent application No. 85 04214, published under the number 2 579 309, to form in the side wall of the header cover apertures which are substantially larger in width than the external diameter of the tubular connectors of the oil cooler. Each of these two apertures may then be closed by an attached plate, which is formed with at least one hole in which one of the tubular connectors is closely engaged, this plate then being secured on the edge of the aperture.
This known solution does enable a header cover to be used which has external dimensions identical to those of a header cover that does not contain an oil cooler. However, it also calls for the provision and fitting of the additional separate plates mentioned above. This is a disadvantage.